Technical Abstract:
Many varieties are better than Russet Burbank in terms of agronomic performance. They have lower sugars, higher marketable yields, a more uniform blocky shape and are easier to grow. However, experience over the past several decades has shown that this is not sufficient for success. For a new variety to succeed, it must match Russet Burbank’s strengths, not just overcome its weaknesses. It has to process well after nine months of storage, and until recently few varieties have been able to do that. It has to have the texture and flavor of Russet Burbank, and this has become the greatest challenge. End users need to supply products with consistent culinary properties and for many products, including frozen fries, tasting different or better is as much a reason for rejection as tasting worse.
The National Fry Processor Trial, in conjunction with the SCRI Acrylamide project, has been evaluating approximately 80 fry processing clones each year since 2011. One goal of both projects is to reduce the acrylamide content of processed potato products relative to current benchmarks. Acrylamide in fries is strongly dependent on the reducing sugar content in raw tubers. As reducing sugar contents increase, the acrylamide content in fries made from them increases. Reducing sugars are typically lowest at the time of harvest and are often highest during the late storage period, when Russet Burbank is the predominant variety being processed. Replacing Russet Burbank with a variety that has low tuber reducing sugar contents during late storage would be a highly efficient way to reduce dietary acrylamide consumption. Trial clones from across the county have been submitted to the NFPT for evaluation. Most clones in these trials have reducing sugar contents lower than standard varieties Russet Burbank and Ranger Russet. Almost half of all clones entered into the trials maintained low tuber reducing sugar contents through the end of the storage period when they were grown in Washington, Idaho, North Dakota and Maine. However, only three percent of clones grown in Wisconsin last year maintained low reducing sugar contents. Many of the clones that have performed best in agronomic trials have undergone extensive sensory evaluations. These evaluations are essential, because clones that deviate too far from the Russet Burbank idea stand little chance of wide-scale acceptance. It is too early to tell if any of the low-sugar clones have sensory attributes similar to Russet Burbank, but the data collected so far suggest that a few of them might. They will receive increased scrutiny in storage trials this year, even as new clones in the NFPT/SCRI trials are being evaluated to see if they overcome Russet Burbank’s weaknesses, and most importantly, to see if they match Russet Burbank’s strengths.